Ask the Fight Doc: Is brain damage possible when chokes are held too long?

While questionable judging calls continue to stir debate among MMA fans and pundits alike, a rash of apparently late stoppages also has supporters of the sport concerned at the long-term effects of such mistakes.

Sure, too many strikes to the head is an obvious concern for fighter safety, but what about choke holds that are applied several seconds after a fighter slips into unconsciousness?

So in our latest “Ask the Fight Doc” installment, MMAjunkie.com medical
consultant and columnist Dr. Johnny Benjamin discusses how exactly choke holds work on the human body and what the dangers are for fighters who aren’t released from the maneuvers in a timely manner.

My inbox has recently been overwhelmed with safety questions regarding chokes – or more specifically, chokes that fans believe were applied for an excessively long period of time. The two examples most commonly mentioned are Sheila Bird’s recent leg-scissor finish of Kim Couture and Richard Hales’s inverted-triangle win over Nik Fekete, both of which resulted in similar outcomes: the recipient being rendered unconscious.

The anatomy of an MMA choke is fairly simple but often misunderstood. MMA chokes that lead to the recipient “going to sleep” (unconscious) primarily deprive the brain of blood flow by compressing the internal carotid artery in the neck. Some fans incorrectly believe that these types of submissions primarily obstruct the windpipe (trachea) making it impossible to breath. Clearly, it is more difficult to breathe with a rear-naked choke correctly applied, but the windpipe is a semi-rigid structure with cartilaginous rings that make it relatively difficult to close shut by externally applied pressure.

Blood flow to the brain is supplied by two major pathways – internal carotid arteries and vertebral arteries. The internal carotid artery lies in the angle formed where the back of the jaw meets the neck and is very susceptible to compression.

Compression of both (one on either side of the neck) carotid arteries for eight-to-10 seconds is likely to render a person unconscious. It takes several minutes of lack of blood flow to the brain (somewhere in the range of four-to-six minutes) before permanent damage to the brain is likely to occur.

If fans believe that a choke was held for roughly 10 seconds after a fighter has lost consciousness, the brain has likely been without adequate blood flow for approximately 20 seconds (remember that it took roughly 10 seconds for the fighter to go to sleep).

In an otherwise healthy athlete, lack of blood flow to the brain for 10-to-20 seconds is not particularly dangerous. Obviously, it’s not a great idea, but once again, it’s not likely to cause permanent damage.

Here’s where things can get a bit tricky and far more dangerous.

In the internal carotid artery lies a very important structure called the carotid sinus or bulb. Next to this artery runs the vagus nerve. Compressing these structures causes the body to respond in some very significant ways – primarily decreasing blood pressure and heart rate. Some people (usually unbeknown to them) can have a hypersensitive carotid sinus which when compressed/stimulated can cause a profound drop in blood pressure and heart rate. In these cases, a dangerously irregular heart beat (arrhythmia) can ensue.

Let’s put it all together.

The choke goes in, and it’s deep. Your carotid arteries are compressed shut thus significantly reducing blood flow to the brain. The carotid sinus and vagus nerves are also compressed and stimulated to drop blood pressure to the body and heart rate. As luck would have it, you are left in the hands of a less-than-attentive or poorly educated referee, and they are slow to recognize your state of altered consciousness.

Your heart rate and blood pressure continue to plummet. If you happen to be one of those uncommon and unfortunate souls that have a hypersensitive carotid sinus, it isn’t going to be lack of blood flow to the brain that does you in. You should be concerned about that wildly irregular heart beat (arrhythmia).

But no worries because you and the ref are both asleep anyway! Night-night.

Dr. Johnny Benjamin is MMAjunkie.com’s medical columnist and consultant and a noted combat-sports specialist. He is also a member of the Association of Boxing Commissions’ MMA Medical Subcommittee. Dr. Benjamin writes an “Ask the Doc” column every two weeks for MMAjunkie.com. To submit a question for a future column, email him at askthedoc [AT] mmajunkie.com, or share your questions and thoughts in the comments section below. You can find Dr. Benjamin online at www.drjohnnybenjamin.com, and you can read his other sports-related articles at blog.drjohnnybenjamin.com.

The Latest

A total of 26 fighters got their chance to shine on Saturday as part of UFC 190 at Rio de Janeiro’s HSBC Arena. Now that UFC 190 is in the books, it’s time to commence MMAjunkie’s “Three Stars” ceremony.

The man known for cranking submissions to the point of injury added eye-gouging to his repertoire. But is the controversy of Rousimar Palhares too essential to his bizarre, awful appeal for his employers to take any meaningful action against him?

Ronda Rousey’s statistical greatness has already ventured into uncharted territory – just six fights into her UFC career. Check out all the post-fight facts, including Rousey’s latest achievements, about UFC 190.